1. Field of the Invention
The present invention relates to a color correcting apparatus for color matching between a plurality of image pickup apparatuses.
2. Description of the Related Art
In using a plurality of video cameras in a broadcasting station, there is a need for strict color matching between the video cameras. Image pickup apparatuses such as broadcasting station cameras, however, have color filters or color separating prisms placed in front of their charge-coupled devices (CCD), and the color filters or color prisms differ slightly from each other in spectroscopic characteristics. Unless such a difference is compensated, image outputs from the apparatuses cannot be made uniform. As means for solving this problem, there is a technique in U.S. Ser. No. 08/667,459 (filed on Jun. 21, 1996) with a title xe2x80x9cVIDEO CAMERA AND VIDEO CAMERA SYSTEMxe2x80x9d, which was assigned to the assignee of the present application, and there is another technique in the application with a tile xe2x80x9cCOLOR CORRECTION APPARATUS, COLOR CORRECTION CONTROLLER, AND COLOR CORRECTION SYSTEMxe2x80x9d, Agent Ref. No. 450100-4105, Assignee Ref. No. S97P817US00 (filed on Sep. 2, 1997). Each of these techniques is based on a process in which colors obtained as a particular color, e.g., each of colors in a color chart by an image pickup apparatus which is used as a reference and with another image pickup apparatus which is subject to color matching with the reference image pickup apparatus are measured under the same condition, and data obtained as the results of this measurement is used to compensate color data which is obtained by the image pickup operation of the image pickup apparatus which is subject to color matching.
The above-described techniques, however, require, for color matching between a plurality of image pickup apparatuses, troublesome operations of designating colors about which color matching will be performed, and measuring each of corresponding colors through the plurality of apparatuses. The above-described techniques also require, for color matching between a plurality of image pickup apparatuses, always setting one image pickup apparatus as a reference and storing color data of this image pickup apparatus. Selection of an image pickup apparatus used as a reference is difficult and a reference image pickup apparatus or color data obtained by a reference image pickup apparatus is always required for color matching. Each of the above-described techniques does not make it unconditionally possible to execute color matching anytime and anywhere, and does not adequately facilitate color matching.
In view of the above-described problems, an object of the present invention is to provide a color correcting apparatus and a color correction control apparatus arranged to easily perform color matching between a plurality of image pickup apparatuses by operating each of the image pickup apparatuses without requiring an image pickup apparatus used as a reference.
Another object of the present invention is to provide a color correcting apparatus and a color correction control apparatus arranged to easily perform color matching with respect to a plurality of colors.
To achieve the above-described objects, according to one aspect of the present invention, there is provided an image pickup apparatus comprising color image pickup means for obtaining a color image pickup signal by converting light from an object into an electrical signal, color correction means for correcting a color of the color image pickup signal based on color correction information, reference color signal forming means for forming a reference color signal for the color image pickup signal, the reference color signal forming means being provided in the image pickup apparatus, error signal output means for detecting a difference between the color image pickup signal and the reference color signal, and for outputting the difference as an error signal, and color correction information forming means for forming the color correction information on the basis of the error signal.
According to another aspect of the present invention, there is provided a color correcting apparatus which corrects a color of a color image pickup signal formed by color image pickup means, the apparatus comprising color correction means for correcting a color of the color image pickup signal based on color correction information, reference color signal forming means for forming a reference color signal for the color image pickup signal, the reference color signal forming means being provided in the color correcting apparatus, error signal output means for detecting a difference between the color image pickup signal and the reference color signal, and for outputting the difference as an error signal, and color correction information forming means for forming the color correction information on the basis of the error signal.